Chapter 7: The Skeleton – Study Guide (BIOL 2301 Human Anatomy & Physiology I)

Chapter 7: The Skeleton

Vocabulary

• Cranium: The portion of the skull that encloses the brain.

• Sutures: Immovable joints between skull bones.

• Cranial vault (calvaria): The superior, dome-shaped portion of the skull.

• Cranial base: The inferior portion of the skull, forming the floor of the cranial cavity.

• Cranial cavity: The space within the skull that houses the brain.

• Sella turcica: A saddle-shaped depression in the sphenoid bone that houses the pituitary gland.

• Cribriform: Refers to the cribriform plate of the ethmoid bone, which contains openings for olfactory nerves.

• Crista galli: A vertical projection of the ethmoid bone, serving as an attachment for the brain's membranes.

• Sutural bones: Small, irregular bones found within sutures of the cranial bones.

• Lacrimal: Refers to the lacrimal bones, which form part of the medial wall of the orbit.

• Intervertebral disc: Pads of fibrocartilage between vertebrae, providing cushioning and flexibility.

• Nucleus pulposus: The inner gelatinous core of an intervertebral disc.

• Anulus fibrosus: The tough, outer ring of an intervertebral disc.

• Herniated (prolapsed) disc: A condition where the nucleus pulposus protrudes through the anulus fibrosus.

• Scoliosis: Lateral curvature of the spine.

• Kyphosis: Excessive posterior curvature of the thoracic spine.

• Lordosis: Excessive anterior curvature of the lumbar spine.

The Skull

Bones of the Skull

The skull is composed of cranial and facial bones, which protect the brain and support facial structures.

• Cranial bones: Include the frontal, parietal, temporal, occipital, sphenoid, and ethmoid bones.

• Facial bones: Include the maxilla, mandible, zygomatic, nasal, lacrimal, palatine, inferior nasal concha, and vomer.

• Important markings: Foramina, processes, and fossae serve as passageways and attachment points.

Example: The sella turcica of the sphenoid bone houses the pituitary gland.

Functions of the Cranium vs. Facial Skeleton

• Cranium: Protects the brain and provides attachment for head muscles.

• Facial skeleton: Forms the framework of the face, contains cavities for sense organs, and provides openings for air and food.

Bony Boundaries of the Orbits and Nasal Cavity

• Orbits: Formed by parts of the frontal, sphenoid, zygomatic, maxilla, palatine, lacrimal, and ethmoid bones.

• Nasal cavity: Bounded by the ethmoid, maxilla, palatine, inferior nasal concha, and vomer bones.

Paranasal Sinuses

• Air-filled spaces in the frontal, sphenoid, ethmoid, and maxillary bones.

• Function: Lighten the skull, enhance voice resonance, and produce mucus.

The Vertebral Column

General Characteristics and Components

The vertebral column supports the body, protects the spinal cord, and allows flexible movement.

• Composed of 26 vertebrae: 7 cervical, 12 thoracic, 5 lumbar, 1 sacrum, 1 coccyx.

• Intervertebral discs separate vertebrae and absorb shock.

Curvatures of the Vertebral Column

• Cervical and lumbar: Concave posteriorly (lordosis).

• Thoracic and sacral: Convex posteriorly (kyphosis).

• Curvatures help maintain balance and absorb shock.

Spinal Curvatures and Intervertebral Discs

• Curvatures and discs allow flexibility and protect against injury.

• Discs consist of a soft nucleus pulposus and a tough anulus fibrosus.

Structure of a Typical Vertebra

• Body (anterior), vertebral arch (posterior), vertebral foramen (spinal cord passage).

• Processes: Spinous, transverse, articular.

Differences Between Cervical, Thoracic, and Lumbar Vertebrae

• Cervical: Small, oval body; transverse foramina; bifid spinous process.

• Thoracic: Larger body; facets for rib articulation; long, downward spinous process.

• Lumbar: Largest body; short, blunt spinous process; no rib facets.

The Thoracic Cage

Bones of the Thoracic Cage

• Sternum, ribs, and thoracic vertebrae.

• Protects heart and lungs; supports shoulder girdles.

True vs. False Ribs

• True ribs (1-7): Attach directly to the sternum via costal cartilage.

• False ribs (8-12): Do not attach directly; ribs 8-10 attach via cartilage of rib 7, ribs 11-12 are floating.

The Pectoral Girdle

Bones Forming the Pectoral Girdle

• Clavicle and scapula.

Structure and Function of the Pectoral Girdle

• Provides attachment for upper limb; allows wide range of motion.

• Clavicle acts as a brace; scapula provides muscle attachment.

Important Bone Markings of the Pectoral Girdle

• Acromion, coracoid process, glenoid cavity (scapula); sternal and acromial ends (clavicle).

The Upper Limb

Bones of the Upper Limb

• Humerus, radius, ulna, carpals, metacarpals, phalanges.

Important Markings of Upper Limb Bones

• Olecranon (ulna), head (radius), greater and lesser tubercles (humerus).

The Pelvic Girdle

Bones Contributing to the Os Coxae

• Ilium, ischium, pubis.

Pelvic Girdle Strength and Function

• Supports body weight; protects pelvic organs; provides attachment for lower limbs.

Differences Between Male and Female Pelves

• Female: Wider, shallower, larger pelvic inlet and outlet for childbirth.

• Male: Narrower, deeper, more robust.

The Lower Limb

Bones of the Lower Limb

• Femur, patella, tibia, fibula, tarsals, metatarsals, phalanges.

Important Markings of Lower Limb Bones

• Greater trochanter (femur), medial malleolus (tibia), lateral malleolus (fibula).

Spinal Disorders

Common Spinal Disorders

• Scoliosis: Lateral curvature of the spine.

• Kyphosis: Excessive thoracic curvature.

• Lordosis: Excessive lumbar curvature.

• Herniated disc: Nucleus pulposus protrudes, causing pain and nerve compression.

Table: Comparison of Vertebrae Types

Type	Body Size	Spinous Process	Special Features
Cervical	Small	Bifid (except C7)	Transverse foramina
Thoracic	Medium	Long, downward	Facets for ribs
Lumbar	Large	Short, blunt	No rib facets

Additional info: Academic context was added to expand brief points and clarify anatomical terms, functions, and comparisons.